The present application claims priority to Japanese Application(s) No(s). P2001-006750 filed Jan. 15, 2001, which application(s) is/are incorporated herein by reference to the extent permitted by law.
The present invention relates to a multi-magnetic recording head, and a magnetic recording method and a magnetic recording apparatus, which use the multi-magnetic recording head. In particular, the present invention relates to a technique of increasing a magnetic recording density of information recorded by a magnetic recording head by configuring the magnetic recording head as a multi-magnetic recording head including a multiplicity of thin film magnetic recording heads.
In recent years, higher magnetic recording density of information recorded on magnetic recording media has been required to increase magnetic recording capacities of the magnetic recording media, and to meet such a requirement, there have been adopted thin film magnetic recording heads suitable for forming narrower recording tracks on magnetic recording media.
To realize higher magnetic recording densities of information recorded on magnetic recording media, that is, larger magnetic recording capacities of the magnetic recording media, it has been required to carry out multi-channel magnetic recording by using a multi-magnetic recording head including a multiplicity of thin film magnetic recording heads.
For example, a known multi-magnetic recording head is configured such that a plurality of thin film magnetic recording heads are arranged on one head substrate (head chip) in such a manner as to be spaced from each other at suitable intervals in the width direction (perpendicular to the gap direction).
FIG. 1 shows a multi-magnetic recording head xe2x80x9caxe2x80x9d including two thin film magnetic recording heads xe2x80x9cbxe2x80x9d arranged in parallel in the width direction.
Each thin film magnetic recording head xe2x80x9cbxe2x80x9d is composed of a lower magnetic pole xe2x80x9cfxe2x80x9d and an upper magnetic pole xe2x80x9cgxe2x80x9d which are stacked on a magnetic shield layer xe2x80x9cexe2x80x9d formed on a non-magnetic substrate xe2x80x9ccxe2x80x9d via an insulating layer xe2x80x9cdxe2x80x9d. These lower magnetic pole xe2x80x9cfxe2x80x9d and the upper magnetic pole xe2x80x9cgxe2x80x9d are two tip portions of a core xe2x80x9chxe2x80x9d which is made from a magnetic material and is formed into an approximately U-shape in a side view. A specific gap xe2x80x9cixe2x80x9d is formed between these lower magnetic pole xe2x80x9cfxe2x80x9d and the upper magnetic pole xe2x80x9cgxe2x80x9d.
A coil xe2x80x9cjxe2x80x9d is wound around the core xe2x80x9chxe2x80x9d. When a current is applied to the coil xe2x80x9cjxe2x80x9d, a magnetic field is generated in the gap xe2x80x9cixe2x80x9d between the lower magnetic pole xe2x80x9cfxe2x80x9d and the upper magnetic pole xe2x80x9cgxe2x80x9d, so that a recording track Tr is formed on a magnetic recording medium (magnetic tape or magnetic disk) xe2x80x9ckxe2x80x9d running in contact with or in the vicinity of the gap xe2x80x9cixe2x80x9d.
The above-described related art multi-magnetic recording head xe2x80x9caxe2x80x9d, however, has a problem that since a gap between the two thin film magnetic recording heads xe2x80x9cbxe2x80x9d cannot be made small, a track pitch Tp of the recording tracks Tr formed on the magnetic recording medium xe2x80x9ckxe2x80x9d becomes relatively large. Accordingly, the related art multi-magnetic recording head cannot record information on a magnetic recording medium at a higher recording density.
To be more specific, since the coil xe2x80x9cjxe2x80x9d wound around the core xe2x80x9chxe2x80x9d necessarily projects sideways from the core xe2x80x9chxe2x80x9d, the adjacent thin film magnetic recording heads xe2x80x9cbxe2x80x9d cannot be arranged in such a manner that the gaps xe2x80x9cixe2x80x9d are close to each other because of interference of the coils xe2x80x9cjxe2x80x9d with each other (see FIG. 2).
For this reason, the recording tracks Tr formed by the thin film magnetic recording heads xe2x80x9cbxe2x80x9d of the multi-magnetic recording head xe2x80x9caxe2x80x9d cannot be made close to each other, and thereby the track pitch Tp of the recording tracks Tr cannot be made narrow. Accordingly, the related art multi-magnetic recording head cannot record information on a magnetic recording medium at a higher recording density (see FIG. 3).
An object of the present invention is to provide a multi-magnetic recording head including a multiplicity of thin film magnetic recording heads, which is capable of increasing a magnetic recording density of information recorded on a magnetic recording medium.
To achieve the above object, according to a first aspect of the present invention, there is provided a multi-magnetic recording head including: a substrate; a pair of first thin film magnetic poles with a specific gap put therebetween, which are stacked over the substrate; and a pair of second thin film magnetic poles with a specific gap put therebetween, which are stacked over the pair of first thin film magnetic poles; wherein the pair of first thin film magnetic poles and the pair of second thin film magnetic poles are offset from each other in the direction nearly perpendicular to the stacking direction.
According to a second aspect of the present invention, there is provided a magnetic recording method of substantially simultaneously forming a plurality of recording tracks by using a multi-magnetic recording head, the multi-magnetic recording head including: a substrate; a pair of first thin film magnetic poles with a specific gap put therebetween, which are stacked over the substrate; and a pair of second thin film magnetic poles with a specific gap put therebetween, which are stacked over the pair of first thin film magnetic poles; wherein the pair of first thin film magnetic poles and the pair of second thin film magnetic poles are offset from each other in the direction nearly perpendicular to the stacking direction.
According to a third aspect of the present invention, there is provided a magnetic recording apparatus including a multi-magnetic recording head, the multi-magnetic recording head including: a substrate; a pair of first thin film magnetic poles with a specific gap put therebetween, which are stacked over the substrate; and a pair of second thin film magnetic poles with a specific gap put therebetween, which are stacked over the pair of first thin film magnetic poles; wherein the pair of first thin film magnetic poles and the pair of second thin film magnetic poles are offset from each other in the direction nearly perpendicular to the stacking direction.
With these configurations, since a plurality of thin film magnetic recording heads are stacked to each other, a width W of the thin film magnetic recording heads can be made small with its accuracy kept at a desirable value, and also an offset between the thin film magnetic recording heads in the width direction, that is, an arrangement pitch P of the thin film magnetic recording heads in the width direction can be made small with its accuracy kept at a desirable value. As a result, the multi-magnetic recording head, and the magnetic recording method and the magnetic recording apparatus, which use the multi-magnetic recording head, according to the present invention are advantageous in increasing a recording density of information recorded on a magnetic recording medium.
According to a fourth aspect of the present invention, there is provided a magnetic recording apparatus including: at least two sets of multi-magnetic recording heads each of which includes a plurality of thin film magnetic recording heads spaced from each other at specific intervals; wherein recording tracks with an unrecorded portion put therebetween are formed by the thin film magnetic recording heads of one of the multi-magnetic recording heads, and a recording track is formed on the unrecorded portion by at least one of the thin film magnetic recording heads of another of the multi-magnetic recording heads.
With this configuration, it is possible to simultaneously form a plurality of recording tracks, and hence to efficiently increase a recording speed of the magnetic recording apparatus.